A centering device of this general type is disclosed in U.S. Pat. No. 3,150,263, issued Sept. 22, 1964 (FIG. 5). The centering device therein disclosed comprises two pneumatically operated crank disks connected together and rotating in opposite directions, each disk being associated with a guide by means of a pair of parallelly pivoted links.
In another cassette positioning device as disclosed in DE-OS 30 00 760, Offenlegungstag July 16, 1981, shifting movement of guide members is accomplished by a motor driven worm gear.
Both of these prior devices are disadvantageous in that the centering and alignment of a film cassette is effected by an abrupt and unabsorbed impact of the guides against the side walls of the cassette. Furthermore, there is no provision for compensating for overtravel of an electric motor in the second device. Moreover, in the case of the first-mentioned device, cassettes of larger sizes can only be precisely and reliably aligned and centered by means of an additional sliding guide engaging the rear end of the cassette and transporting the cassette over the last portion of its path to the loading and unloading station.